Electric-current rectifier



- Noir. 15, 1927.

s. RUBEN I ELECTRIC CURRENT RECTIFIER Filed Jan. 2,- 1925 gwbemfidz SAMUEL RUBEN 351 ll 3 clam/ 1n.

Patented Nov. 15 1927.-

UNITED STATES 1,649,743 PATENT OFFICE.

SAMUEL, RUBEN,- Oil-NEW YORK, N. m, ASSIGNOB, BY mnsNn ASSIGNMENTS, 'ro

' RUBEN nnc'rrrrrga CORPORATION or. DELAWARE.

ELECTRIC-CURRENT RECTIFIER.

Application filed January 2, 1925. Serial No. 155.

This invention relates to electric current rectifiers and the like and particularly to electrode elements which are adapted to pro- .vide an asymmetric couple of the drysurface contact variety. 4 e

The object generally of the invention is to provide a device of this character which'is economical, efficient and readily manufactured. p v

More specifically, an object of the invention is to provide an arrangement of electrode elements which is adapted for high duty service in rectification and the like when one of theelements has a particular composition, or specifically, when the electropositive element is made of a substantially nonoxidizable compound. v

Other objects of the invention will in part be obvious and will'in part'appear herein 2 after. I v

The invention accordingly comprises the features 'of construction, combinations of elements, will be exemplified in the constructions here 2 inafter set forth and the scope of the application of which will be indicated in the claims.

The present application is a continuation in part of my prior and co-pending applicationyserial No. 7 50,539, filed November 18,

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawing, in which the figure is a view showing, partly diagrammatically and partly in section, a rectifying device constructed in accordance with the present invention ar- 7 ranged for battery-charging service.-

In the practice of the resent invention a dry surface-contact rectifying device is-provided, having as one electrode a substantially non-oxidizing aluminum compound, such as aluminum and mercury, aluminumand mag- I nesium, or aluminum, magnesium and mercury, in surface contact with a cooperat1ng electrode composed of a' material which is also substantially non-oxidizing at operating conditions-or temperatures, such as silver sulphide, or with an oxidizable 'electronegative material, such as cupric sulphide or both, suitable precautions being taken to prevent the formation of'oxides at the contacting areas, when. an oxidizable material is so and arrangement of parts,'which employed, Rectification in this unit, as in that described in my said prio'r application, 1s effected through unilateral conduction; that is, current flowsthrough the unit only when the electropositi've aluminum compound electrode is negatively charged,-and will not flow when that element functions as the anode in the circuit, The probable resultant effect of the reaction between the aluminum electrode and the sulphide electrode is the formation of an i aluminum sulphide film. lVhn current of excessively high densities s applied to the rectifying unit described in my said prior application, the effect of the heat developed thereby at the "juncture of the electrodes is to produce a cuprous oxide coating upon the contacting-surfaces. This occurs, however, only when the heat resulting from such a discharge is suliicient to cause thatreaction. With the-continued application of such a current, this action goes on over' the entire contacting areas, until the increased electrical resistance developed by this product of. the reaction,"- materially lowers the efficiency of the unit.

This reaction can'be substantially com-' pletely avoided by using, as the electrode in combination and in surface contact with the aluminum compound electrode, a sulphide compound which will not form an 0X' ide, or which by the intimacy of contact, can not oxidize over the contacting areas, and which will permit continuous operation of the couple at relatively high current den- 4 sities. p

Silver sulphide, as a non-oxidizing compound, is well adapted to this use, applied to the surface as a coating of the aluminum electrode, applied in any suitable manner, as in solution with a binder, or as a thin contacting plate. Likewise, cu ric sulphide is well adapted to this use, ut, best when employed as an electrode coating applied as a fine powder in solution with an inert'binder, such as gum arabic; a combination of both of these materials, mixed and so a plied, has certain advantages, in that t e relatively high,- resistance of the silver sulphide element is counter-balanced by the relatively lowresistance of .the'cupric sul- 1 phide, which latter readily gives up its sulphur to the silver metal should the silver sulphide lose .its sulphur element through vaporization of that element, due to excessive heat, or otherwise, reestablishing the sil- 1 performance, without the use of any con-* constant,

ver sulphide coating area. Due to the close surface contact of the cupric sulphide with the aluminum electrode, no air can reach that area, and hence no cuprous oxide can be formed thereby. The cupric sulphide sulphur supplying element can also be supplied by the employment of a coating of this material upon a conductive material in close surface contact with the silver sulphide electrode.

For normal operating conditions, the sil ver sulphide electrode is satisfactory in its tacting sulphur bearing body. Employed as a coating a thickness of .1 millim ter is suificiena y the employment of either sulphide electrode in the manner described, the production of any oxide in the area of the electrode junctures is avoided, as is also the building up of an electrical resistance inv the operation of this'type of rectifiein,

The assembled rectifying unit is substantially unilaterally conductive or rectifying, without any necessity for first applyin an inverse or formation current, its a ternating current application being practically and withno sparking between the electrodes Besides being adapted to alternating current rectification, such a couple is equally welladapted for other uses, such as a high capacity condenser and as an automatic di rect current cut-off relay. As a cut-off relay,

when the potential of a storage battery or' other unit in a charging circuit, becomes higher than the potential of the generator, or charging source, the direct current supply is cut off, and here is no discharge from the stora ebattery to the source.

' their surfaces adjacent the on no sulphide Bolt plates 2, and them tive po e of battery .13 is connected to t e copper end plates. N holds the various conductive .plates and the electrodes3- and 3,, in close surface contact, it being insulated therefrom by fibre tube D and by insulating end washers '4. By this arran ment, the devices being charged can not barge any measurable current through the rectifier. T is a stepdown. transformer for the reduction of potential' for battery charging, and G is the supplying the input current. At

dicated by arrows d, and 03,; upon the re versal of polarity of the current, the current flows as indicated by arrows (Z and d rectif ying the applied alternating current, and permitting the application of direct current to the output terminals 0, and 0,. The

battery receives a charge when the output direct current potential is greater than its own; but, should this potential be reduced below that of the generator, the battery will not discharge in the opposite direction because of the practically open circuit resistance of the aluminum mercury electrode, when connnected as an anode.

Having described my invention, what I claim as new and desire to secure by Letters Patent is v 1. In dry surface-contact rectifying devices and the like, an asymmetric electric couple comprising an electropositive electrode element composed of a compound of aluminum and a composite electronegative electrode element having as one component a. metallic sulphide, substantially resistant to electro-chemical oxidation.

cou le comprising an electropositive elec-- ,tro e element composed of an amalgam contaming aluminum and a composlte electro- -negative electrode element containing a metallic sulphide adapted to resist electrochemical oxidation.

4. In dry surface-contact rectifying devices and the like, an asymmetric electric couple comprising an electropositive electrode element composed of an amalgam of an allo of aluminum and an electronegative electro e element disposed and arranged to apply a non-oxidizable surface of silver sulphide in contact with said electropositive element.

'5. In dry surface-contact rectifying devices and the like, an asymmetric electric couple comprising an electropositive electrode element composed of a relatively highly electropositive metallic element and an electronegative electrode element composed of an electrically conducting metallic sulphide and an interposed layer of silver sulphide.

6. dry surface-contact rectifying de- Y ponent composed of an electrically conduct-.

' pric sulphide.

vices and the like, an asymmetric electric couple comprising an electropositive electrode element composed of an aluminum compound, a coating of silver sulphide disposed in contact with said aluminum compound and an elect ronegative electrode com ing metallic sulphide coo eratively disposed against said silversulphi e.

7, A current ectifier of the type described, havinga pair of electrodes, one of which is an. aluminum compound, and the current rectifier of the type described, having a pair-of electrodes, one of,

which is an alloy of aluminum and mercury, and the other of which is silver sulphide between and in surface contact with said aluminum alloy electrode and a body composed of cupric sulphide. 10. A current rectifier of the type described, having a pair of electrodes, one of which is an electropositive material, and the other of which is a composite body having a cooperating layer of silver sulphide, said a body composed of a copper compound, said silver sulphide coating being applied with a fluid binding material to the surface of said electropositive material.

11. 'A current rectifier of the type described, having a pair of electrodes, one of which is an electropositive material, and the other of which is a composite body having a cooperating layer of silver sulphide, sai body composed of a coppercompound, said silver sulphidecoating being applied with a fluid bindingmaterial to the surface of said other electrode.

l2. A current rectifier of the type described, having a pair of electrodes, one of which is an electropositive material, and the other of which contains silver sulphide and cupric sulphide.

'13. A current rectifier of the. type described, having a pair of electrodes, one of which is an'electropositive material, and the other of which contains silver sulphide and eupric sulphide, said other electrode being applied as a coating upon. a surface, of said electro-positive electrode, as powder in solution with an inert binder. p 14. A current rectifier of the type described, having a pair of electrodes, one of which is an electro positive material, and the other of which contains silver sulphide and cupric sulphide, said other electrode being applied as a coating upon asurface'of said electro-positive electrode, as powder in solution with an inert'binder, 'saidbinder comprising gum arabic.

Signed at New York in the county of New York and State of New York this 8th day of December, A. D. 1924. i

SAMUEL RUBEN. 

